[btrfs-devel][patch]Cache blocks in the hole at beginning of a block group

[Yan Zheng]

Hello everyone.

Please consider this patch, the original one has duplicate codes in
the loop body. The only change in this one is move the duplicate codes
out from the loop body.

Regards
YZ

diff -r 0d4a5b197024 extent-tree.c
--- a/extent-tree.c	Tue Sep 11 19:45:31 2007 -0400
+++ b/extent-tree.c	Fri Sep 14 23:21:08 2007 +0800
@@ -39,6 +39,7 @@ static int cache_block_group(struct btrf
 	u64 i;
 	u64 last = 0;
 	u64 hole_size;
+	u64 first_free;
 	int found = 0;

 	root = root->fs_info->extent_root;
@@ -52,6 +53,7 @@ static int cache_block_group(struct btrf
 	if (!path)
 		return -ENOMEM;
 	path->reada = 2;
+	first_free = block_group->key.objectid;
 	key.objectid = block_group->key.objectid;
 	key.flags = 0;
 	key.offset = 0;
@@ -71,50 +73,45 @@ static int cache_block_group(struct btrf
 			if (ret == 0) {
 				continue;
 			} else {
-				if (found) {
-					hole_size = block_group->key.objectid +
-						block_group->key.offset - last;
-				} else {
-					last = block_group->key.objectid;
-					hole_size = block_group->key.offset;
-				}
-				for (i = 0; i < hole_size; i++) {
-					set_radix_bit(extent_radix,
-						      last + i);
-				}
 				break;
 			}
 		}
 		btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
+		if (key.objectid < block_group->key.objectid) {
+			if (key.objectid + key.offset > first_free)
+				first_free = key.objectid + key.offset;
+			goto next;
+		}
 		if (key.objectid >= block_group->key.objectid +
 		    block_group->key.offset) {
-			if (found) {
-				hole_size = block_group->key.objectid +
-					block_group->key.offset - last;
-			} else {
-				last = block_group->key.objectid;
-				hole_size = block_group->key.offset;
-			}
+			break;
+		}
+		if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
+			if (!found) {
+				last = first_free;
+				found = 1;
+			}
+			hole_size = key.objectid - last;
 			for (i = 0; i < hole_size; i++) {
 				set_radix_bit(extent_radix, last + i);
 			}
-			break;
-		}
-		if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
-			if (!found) {
-				last = key.objectid + key.offset;
-				found = 1;
-			} else {
-				hole_size = key.objectid - last;
-				for (i = 0; i < hole_size; i++) {
-					set_radix_bit(extent_radix, last + i);
-				}
-				last = key.objectid + key.offset;
-			}
-		}
+			last = key.objectid + key.offset;
+		}
+next:
 		path->slots[0]++;
 	}

+	if (!found)
+		last = first_free;
+	if (block_group->key.objectid +
+	    block_group->key.offset > last) {
+		hole_size = block_group->key.objectid +
+			block_group->key.offset - last;
+		for (i = 0; i < hole_size; i++) {
+			set_radix_bit(extent_radix,
+					last + i);
+		}
+	}
 	block_group->cached = 1;
 err:
 	btrfs_free_path(path);
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